U.S. patent number 5,894,130 [Application Number 08/907,536] was granted by the patent office on 1999-04-13 for ultraviolet sterilization unit.
This patent grant is currently assigned to Aquatron, Inc.. Invention is credited to Stanley W. Bach.
United States Patent |
5,894,130 |
Bach |
April 13, 1999 |
Ultraviolet sterilization unit
Abstract
An ultraviolet sterilization unit having a housing attached to
an air heating and cooling system. The housing including two
apertures into which lamp cartridges are inserted. The lamp
cartridges carrying ultraviolet lamps operating in a frequency
capable of sterilizing air within the system. The cartridges are
configured to automatically de-energize the lamps when a lamp
cartridge is removed from the housing. When the sterilization unit
is a multiple lamp system, when one of the lamp cartridges is
removed all lamps are de-energized. The de-energizing of the lamps
occurring before a user will view the lamp.
Inventors: |
Bach; Stanley W. (Moreland
Hills, OH) |
Assignee: |
Aquatron, Inc. (Solon,
OH)
|
Family
ID: |
25424268 |
Appl.
No.: |
08/907,536 |
Filed: |
August 8, 1997 |
Current U.S.
Class: |
250/436;
250/504R; 422/24; 422/121 |
Current CPC
Class: |
A61L
2/10 (20130101) |
Current International
Class: |
A61L
2/10 (20060101); A61L 002/10 () |
Field of
Search: |
;250/436,455.11,54R
;422/24,121 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
"Air Irradiation in Heating and Air-Conditioning Ducts", pp.5-9
(untitled, undated publication). .
"Sterilamp Germicidal Ultraviolet Tubes", Westinghouse, pp. 11, 8,
13, 5 and 3, (undated publication). .
"What are American Ultraviolet sterile conditioners?", 4 pp.,
untitled, undated publication..
|
Primary Examiner: Berman; Jack I.
Attorney, Agent or Firm: Fay, Sharpe, Beall, Fagan, Minnich
& McKee
Claims
Having thus described the invention, it is now claimed:
1. An ultraviolet sterilization unit comprising:
a lamp cartridge configured to hold an ultraviolet lamp, and a
first portion of an electric circuit for energizing the ultraviolet
lamp; and
a housing including an aperture into which at least a portion of
the lamp cartridge is inserted, and a second portion of an electric
circuit for energizing the ultraviolet lamp, the second portion
configured to connect to the first portion when the lamp cartridge
is inserted into the aperture,
wherein the ultraviolet lamp is only energized when the lamp
cartridge is inserted in the housing.
2. The ultraviolet sterilization unit according to claim 1 wherein
the housing is configured to accept a plurality of lamp
cartridges.
3. The ultraviolet sterilization unit according to claim 2 wherein
the second portion includes a ballast and cartridge socket for each
lamp cartridge, and the second portion is configured such that
removal of any lamp cartridge from the housing de-energizes all the
lamps carried by the lamp cartridges.
4. The ultraviolet sterilization unit according to claim 3 wherein
the lamps inserted in the housing are offset from each other,
thereby increasing the area of effective irradiation.
5. The ultraviolet sterilization unit according to claim 1 wherein
the ultraviolet lamp operates in a wavelength range of 253.7 nm,
which is optimal for destroying air borne micro-organisms.
6. The ultraviolet sterilization unit according to claim 1 wherein
the ultraviolet lamp is a single end lamp.
7. The ultraviolet sterilization unit according to claim 1 wherein
the ultraviolet lamp is a double end lamp, and the lamp cartridge
includes an external connector and external wires to complete an
electric path for the double end lamp.
8. The ultraviolet sterilization unit according to claim 1 wherein
the housing is configured to be attached to a section of an air
heating and cooling system.
9. The ultraviolet sterilization unit according to claim 8 wherein
the housing is capable of being attached to the section of the air
heating and cooling system at a plurality of angles.
10. The ultraviolet sterilization unit according to claim 1 wherein
the lamp cartridge further includes a handle portion for gripping
by a user.
11. The ultraviolet sterilization unit according to claim 1 wherein
the housing further includes a lamp indicator which allows an
external indication of the status of an energized lamp.
12. The ultraviolet sterilization unit according to claim 1 wherein
the first portion of the electric circuit of the lamp cartridge
further includes, i) a lamp holder for holding one end of the
ultraviolet lamp, ii) a lamp socket which connects to prongs of the
ultraviolet lamp, iii) a cartridge plug configured to connect to
the second portion carried by the housing, iv) a mounting plate
including apertures for holding the plug cartridge and the lamp
socket and v) a cap including a handle portion for gripping the
lamp cartridge.
13. The ultraviolet sterilization unit according to claim 1 wherein
the second portion of the electric circuit of the housing includes,
i) a ballast powered by an external power source, ii) a cartridge
socket electrically connected to the ballast and further configured
to connect to the first portion carried by the lamp cartridge.
14. The ultraviolet sterilization unit according to claim 1 wherein
the unit is powered by a 110 VAC.
15. A method of irradiating air borne micro-organisms in an air
heating and cooling system comprising:
cutting at least one opening in a section of the air heating and
cooling system, in accordance with a predetermined pattern;
attaching a housing to the section of the air heating and cooling
system which has been cut according to the predetermined pattern,
the housing including an aperture aligned with the at least one
opening in the air heating and cooling system, and further
including a first portion of an electric circuit; and
inserting a lamp cartridge having an ultraviolet lamp connected to
a second portion of an electric circuit, into the housing aperture
until the first portion and second portion are electrically
connected, wherein the ultraviolet lamp is energized when the first
and second portions are in electrical connection.
16. The method according to claim 15 further including applying
removal-force causing the first portion and the second portion to
become disconnected.
17. The method according to claim 15 further including providing a
housing gasket to the cut section of the air heating and cooling
system, such that the housing gasket is between the cut section and
the housing, to stop air leakage.
18. The method according to claim 15 further including providing
the housing with a plurality of apertures to accept a plurality of
lamp cartridges.
19. The method according to claim 18 further including the step of
de-energizing all inserted lamp cartridges when one lamp cartridge
is removed.
20. The method according to claim 18 wherein a lamp cartridge is
energized only after the ultraviolet lamp has been sufficiently
inserted into the air heating and cooling system such that no
ultraviolet rays will be emitted externally of the system.
Description
BACKGROUND OF THE INVENTION
This invention pertains to the art of ultraviolet germicidal lamps
used for air sterilization.
The invention is applicable to compact ultraviolet germicidal
sterilization units which are inserted within the air ducts of
forced air heating and cooling systems, and will be described with
particular reference thereto. It will be appreciated, however, that
the invention has broader applications and may be advantageously
employed in other environments and applications that benefit from
the sterilization of recirculated air.
Ultraviolet energy which can be grouped into three wavelength
categories, "long," "middle," and "short" wave ultraviolet, has
been shown to be beneficial for a variety of uses. All of
ultraviolet wavelengths are shorter than visible light waves and,
therefore, are invisible to the human eye.
It has been further shown that ultraviolet wavelengths in the short
wave category, and in particular in the region of 253.7 nm, are
useful in the destruction of bacteria and other micro-organisms in
the air or on exposed surfaces. Micro-organisms which are invisible
to the unaided eye, include bacteria, mold spores, yeast and
viruses. Each of these are microbes, but different from each other.
Microbes are living cells approximately 1/25,000 of an inch in
length which reproduce by one cell dividing every twenty minutes or
faster. This is a continuous cycle and, if left unchecked, from one
bacteria there would be several billion bacteria in less than
twelve hours. Indoor air may contain countless bacteria and mold
spores and/or viruses, which are the source of spoilage of
perishable products and the cause of disease in humans and animals.
Germicidal rays emitted by ultraviolet lamps in the short
wavelengths in the range of 253.7 nm travel through the air and
destroy micro-organisms which are in the path of the rays.
In order for the ultraviolet rays to kill bacteria, etc., the rays
must directly strike the micro-organisms. Thus, micro-organisms
floating in the air may easily be reached by the ultraviolet rays
and, therefore, are readily destroyed. Exposure to ultraviolet rays
necessary to kill bacteria, etc. is the product of time and
intensity. High intensity for a short period of time, or low
intensity for a long period are fundamentally equal in lethal
action on bacteria (disregarding the life cycle of the
bacteria).
It has been found that the characteristics of germicidal
ultraviolet, i.e. those rays in the short wavelength region of
253.7 nm, are useful in air heating and cooling systems to make the
air passing through system ducts equivalent, as much as possible,
to outdoor air in freedom from live bacteria, etc.
In the average installation, a 90% kill of air borne bacteria,
equivalent to most outside air, is recommended. Where a maximum
sterilization is imperative, as in hospitals and pharmaceutical
laboratories, the highest bacterial reduction possible is
desirable--at least 98%. Such conditions can be obtained by
increasing the number of lamps in the air conditioning system.
Since the effectiveness of their radiation increases with time of
exposure, ultraviolet (germicidal) are known to be installed in the
part of the heating and cooling system where the air velocity is
the lowest. It has been determined that placement after the
filters, if at all possible, is optimal.
A specific example of existing ultraviolet sterilization equipment
inserted within forced air heating and cooling system A is
illustrated in FIG. 1. Sterilization equipment B is located at an
intake end of cool air return duct D, and sterilization equipment C
is located in a centralized area of cool air return duct D. A
preferred location for placement of sterilization equipment C is
within the cool air return D. While ultraviolet lamps can be placed
on the warm air side of the system, this tends to decrease the life
of the ultraviolet lamps. As can be seen more closely in FIGS.
2a-2c, such lamps are presently arranged in a variety of
configurations, including FIG. 2a which is a lamp holder E with one
lamp F, FIG. 2b a lamp holder G with two lamps H, I as well as FIG.
2c which is a sixteen lamp grid J arrangement four feet square by
eighteen inches deep. Thus, existing units may be used in a small
installations such as found in homes, as well as in larger
industrial type heating/air conditioning systems found in
commercial buildings.
A drawback known to exist in using germicidal ultraviolet lamps for
sterilizing recirculating air is that the rays from ultraviolet
lamps are harmful to the eyes and skin of humans and animals.
For this reason, in personal protection applications, that is, the
use of the lamps for room irradiation in homes, schools, offices,
etc., indirect fixtures are placed on the wall or suspended from
the ceiling above eye level. Only the upper air is irradiated and
the people occupying the room should receive no direct radiation.
It is also known that plant life may be damaged by direct or
reflected germicidal ultraviolet rays and transient dyes and colors
will fade from exposure to ultraviolet rays.
When sterilization equipment such as B and C are within the forced
air heating and cooling system A, there is no concern as to harm to
humans, animals, plants, etc. However, over time the lamps degrade
and need to be replaced. Also, it is important that functioning
lamps be kept on a maintenance schedule which includes cleaning and
inspection. Dust in the air within air ducts tend to cover the
lamps, thereby degrading their usefulness by limiting the intensity
and amount of ultraviolet rays emitted. Cleaning, inspection and
replacement of lamps require complete removal of equipment B and C
from heating and cooling system A.
A concern with removal of such sterilization equipment is the
possibility of harm being caused due to the lamps being removed
while they are energized. Manufacturers of these units address the
issue of safety by requiring large "Caution" notices and other
warnings near the lamp fixtures instructing a person to ensure that
they de-energize the lamps prior to working near the installation.
The commonly suggested warning is that no one should look directly
at a lighted lamp, or work near a lighted lamp without adequate eye
protection. It is further suggested that tube and reflector
cleaning and tube replacement should be entrusted only to personnel
who will observe the strict precaution of never exposing the face
and eyes to a lighted tube while they are working on it or on the
reflector. It is noted that reflectors are often used to direct the
rays of the lamps in installations.
In larger units such as the sixteen lamp configuration J shown in
FIG. 2e, it is possible to provide an access door for periodic
checking and cleaning of the lamps in a chamber or air duct in
which the lamps are mounted. As a safety measure, some
installations configure the door so it is locked with an electrical
circuit such that the lamps are turned off automatically when the
door is open. Further, a window of ordinary glass, which filters
out the ultraviolet, is provided to allow safe observation of the
lamps.
Thus, as illustrated in FIGS. 1 and 2, for small size
installations, such as household use, etc. the manner of ensuring
that harmful rays are not viewed by a user replacing or cleaning
ultraviolet lamps, is the use of a "caution" notice. However, in
many instances such caution notices are either ignored,
accidentally removed, or otherwise not effective, resulting in a
user looking directly at an energized lamp, without adequate eye
protection.
Further, while there is a certain degree of control in large
industrial settings, such as ensuring automatic turn off of the
lamps when a door is open, these turn offs are not implemented in
the smaller sized settings. Particularly, in the smaller
installations no access door provided, due in part to size
constraints. In view of the foregoing, if there is an increase in
the number of sterilization units used in residential or smaller
settings, there will likely be a corresponding increase in the
number of users forgetting or ignoring instructions to de-energize
the lamps and/or otherwise not following the proper precautions
resulting in an increase in injuries.
Thus, there has not been a wide use of ultraviolet sterilization
equipment in residential or smaller installations where
de-energizing of the lamps is not ensured. This is in part due to
manufacturers' concerns of being liable for injuries sustained by a
person misusing the sterilization equipment. The above factors
result in an undesirable situation where bacteria and other
micro-organisms, which would otherwise be destroyed, through
application of ultraviolet rays are recirculated through an air
heating and cooling systems thereby increasing the spread of
viruses, bacteria, etc. in these settings.
Therefore, it has been deemed desirable to develop an ultraviolet
sterilization unit for use in forced air heating and cooling
systems which ensures the turning off/de-energizing of an
ultraviolet lamp prior to exposing the lamp to the view of a user.
Further, the ultraviolet sterilization unit should be compact and
easy to insert within the air heating and cooling ducts thereby
encouraging those with limited mechanical capabilities to install
the unit. Still further, the ultraviolet sterilization unit should
be configured for use with multiple lamps and should ensure the
turning off of all lamps in the multiple lamp unit when any one of
the lamps is removed and/or exposed to human view.
SUMMARY OF THE INVENTION
The present invention contemplates a new and improved ultraviolet
sterilization unit that overcomes all of the above noted problems
and others, and full proofs the turning off of all lamps within the
unit when any one lamp is removed and/or exposed to human view.
According to a more limited aspect of the invention, the
ultraviolet sterilization unit is made to be easily attached and
inserted into an air heating and cooling system, causing minimal
disruption of the air heating and cooling system.
According to yet another aspect of the invention, ultraviolet lamps
in a multiple lamp unit are offset from each other thereby
increasing the area irradiated by ultraviolet rays.
According to still a further aspect of the invention, the
ultraviolet sterilization unit is configured such that it may be
rotated 90.degree. to locate lamps at right angles to the air flow
thereby increasing the air flow irradiated by the ultraviolet
rays.
A principal advantage of the invention is provision of an
ultraviolet sterilization unit that eliminates a high percentage of
air borne micro-organisms in recirculated air and which ensures
safe removal of an ultraviolet lamp of the unit by automatically
de-energizing all lamps within a unit upon removal of any one
lamp.
Another advantage of the invention resides in the ease with which
the unit may be attached and inserted into an existing air heating
and cooling system.
Still other advantages and benefits of the invention will become
apparent to those skilled in the art upon a reading and
understanding of the detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention may take physical form in certain parts and
arrangements of parts, a preferred embodiment of which will be
described in detail in this specification and illustrated in the
accompanying drawings which form a part hereof and wherein:
FIG. 1 is an air heating and cooling system with existing
sterilization equipment;
FIGS. 2a-2c are a variety of existing ultraviolet sterilization
lamp configuration;
FIG. 3 is an air heating and cooling system incorporating an
ultraviolet sterilization unit according to the teachings of the
present invention;
FIG. 4 is an expanded view of a section of FIG. 3 providing a side
view of the ultraviolet sterilization unit of the present
invention;
FIG. 5a depicts a single lamp cartridge including an ultraviolet
lamp, according to the teachings of the present invention;
FIG. 5b is an exploded view of FIG. 5a;
FIG. 6a depicts an ultraviolet sterilization unit of the present
invention implemented in a two lamp configuration;
FIG. 6b is an exploded view of FIG. 6a;
FIG. 7a depicts an alternative view of the ultraviolet
sterilization unit of FIG. 6a;
FIG. 7b is an exploded view of FIG. 7a;
FIG. 8 is a schematic of a dual lamp ultraviolet sterilization unit
according to the teachings of FIGS. 6a-7b;
FIG. 9 is a cross-sectional view of the ultraviolet sterilization
unit shown in FIGS. 6a-7b; and,
FIG. 10 illustrates a lamp cartridge for a two ended ultraviolet
lamp.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings wherein the showings are for purposes
of illustrating a preferred embodiment of the invention only and
not for purposes of limiting same, FIGS. 1 and 2a-2b illustrate the
previous discussed ultraviolet sterilization equipment arranged to
be included within a forced air heating and cooling system.
FIG. 3 depicts a forced air heating and cooling system A such as
that in FIG. 1. However, in this embodiment, ultraviolet
sterilization unit 10, configured according to the teachings of the
present invention, has been inserted within the cool air return 12
of air heating and cooling system A. Although not shown,
ultraviolet sterilization unit 10 may also be placed in other
locations within system A including the connection 14 between cool
air return 12 and heating/cooling unit 16. Ultraviolet
sterilization unit 10 is provided with power through power cord 18
which is connected to a normal household outlet 20 and
sterilization unit 10. It is to be appreciated that other known
sources of power may also be used.
FIG. 4 is a side view of ultraviolet sterilization unit 10 inserted
through, a cut-away section of the duct work of cool air return 12.
Ultraviolet sterilization unit 10 of FIG. 4 includes two
ultraviolet lamp cartridges 22, 24 holding ultraviolet lamps 26 and
28 and carried within main housing 30.
Turning attention to FIGS. 5a and 5b, lamp cartridges 22 and 24
will be described in greater detail. It is to be appreciated the
following discussion is equally applicable for both cartridges 22
and 24, with FIG. 5a depicting an assembled lamp cartridge 22 (24).
FIG. 5b is an exploded view of FIG. 5a, where ultraviolet
(germicidal) lamp 26 (28) is aligned for insertion within lamp
holder 32. Lamp holder 32 may be of different configurations, but
includes a manner of gripping ultraviolet lamp 26 (28) in a secure
fashion.
It is to be appreciated that a variety of different ultraviolet
lamps may be used in sterilization unit 10, including a single
ended germicidal lamp such as those sold under the STERILAMP brand
name (STERILAMP is a trademark of Westinghouse Corporation).
Particular lamps of this type include slimline lamps (G36T6L and
G1051/2H) which are designed for sterilization applications. Their
high ultraviolet output permits the efficient radiation of rapidly
moving air. At the 300 to 400 milli-amp current loading the
moderate cooling of the bulb system increases, rather than
decreases the ultraviolet output. These lamps are effective
germicidal lamps for residential-sized forced air heating and
cooling systems.
With continued attention to FIG. 5b, mounting plate 34 is
configured with apertures sized to receive and hold cartridge plug
36 and lamp socket 38, which is designed to receive the prongs of
ultraviolet lamp 26 (28). For ease of explanation, FIG. 5b does not
show the required wiring necessary for lamp cartridge 22 (24),
including the wiring for cartridge plug 36 and lamp socket 38.
However, these wiring connections, as well as the wiring
connections necessary for a two lamp ultraviolet sterilization unit
10, are illustrated in FIG. 8 and will be discussed therein. It is
to also be noted that while cartridge plug 36 is shown as a four
terminal connection, which is sufficient for a single lamp
cartridge 22 (24), a six pin cartridge plug is used for the two
lamp unit described in FIG. 8.
Lamp cartridge 22 (24) further includes cap 40 within which are
held portions of lamp socket 38, cartridge plug 36 and wirings
associated therewith. Cap 40 is also configured to include a handle
portion 42 and 44 (shown in FIGS. 6a, 6b) allowing for easy
gripping of the lamp cartridge 22 (24).
FIG. 6a shows lamp cartridges 22 and 24 inserted within main
housing 30. FIG. 6b is an exploded front view of main housing 30
and associated lamp cartridges 22, 24, where housing 30 includes
ballasts 46 and 48, each associated with one of respective lamp
cartridges 22 and 24. Cartridge sockets 50 and 52 are provided for
interconnection with cartridge plugs 36 and 37 (shown in FIG.
7b).
Housing cover 53 includes apertures 54 and 56 into which light
pipes 58 and 60 are inserted. A housing plate 62 engages with the
housing cover 53 to maintain ballast 46 and 48, as well as
cartridge sockets 50, 52 and light pipes 58 and 60 internal of
housing cover 53 and housing plate 62. Light pipes 56 and 58 are
used to allow a user to observe whether energized ultraviolet lamps
within a system are functioning, as the light pipes 58, 60 become
illuminated when in contact with ultraviolet rays in the short wave
lengths. Housing cover 53 also includes apertures 55a, 55b which
are sized to securely receive cap 40.
It is noted that the wiring for ballast 46 and 48 in the present
embodiment are more particularly illustrated in FIG. 8. The wirings
are not included in these figures to ease the understanding of the
construction of ultraviolet sterilization unit 10.
To further explain the present invention, a back side view of main
housing 30 is provided in FIG. 7a, with an exploded view of FIG. 7a
shown in FIG. 7b. FIG. 7b more clearly sets out that cartridge
sockets 50 and 52 are placed within apertures of housing cover 53
such that they are capable of engaging lamp sockets 36 and 37 of
lamp cartridges 22 and 24.
It is to be noted that lamp cartridges 22 and 24 are constructed
such that ultraviolet lamps 26 and 28 are in an offset relationship
with each other. In particular, they are not located within the
same plane. This configuration is provided so as to provide a
broader coverage of sterilization within the air ducts. However, a
sterilization unit without the offsetting can also be constructed
according to the teachings of the present invention.
When lamp cartridges 22 and 24 are inserted into main housing 30,
lamp holders 32 and 33 are engaged by lamp holder recepticles 32'
and 33'. This arrangement increases the stability of the inserted
lamps 26 and 28. Also, when lamp cartridges 22 and 24 are inserted
into main housing 30, cartridge sockets 50 and 52 are respectively
aligned and engaged with cartridge plugs 36 and 37.
As will be further discussed in connection with FIG. 8, the
connections of cartridge plugs 36 and 37 with cartridge sockets 50
and 52 energize ultraviolet lamps 26 and 28. Thus, when in an
engaged position such as shown in FIGS. 6a and 7a, ultraviolet
lamps 26 and 28 are energized and, therefore, actively sterilizing
circulating air.
Lamp cartridge 22 (24) can be removed from main housing 30 by
applying removal force to handle 42 (44). This action disengages
lamp holder 32 (33) from lamp holder connector 32' (33'), as well
as disconnects cartridge socket 50 (52) from cartridge plug 36
(37). By breaking the connection between the cartridge socket and
cartridge plug, the ultraviolet lamp 26 (28) is de-energized. Thus,
the lamps are de-energized and no ultraviolet rays are radiated to
a user viewing the ultraviolet lamps 26 and 28. In this manner, a
user is automatically protected from harmful ultraviolet rays.
Lamp cartridges 22, 24 will be removed from main housing 30 to
either replace ultraviolet lamps 26, 28 within the respective
cartridge or to clean lamps 26, 28 to allow them to maintain
maximum output. The frequency of cleaning will vary with the
condition surrounding the particular installation, however, it is
recommended that the cleaning cycle should, under no condition,
exceed six months.
To remove lamps 26 and/or 28 from cartridge holders 22 and/or 24 a
user can push, twist and pull to unlock and remove the lamps from
lamp cartridges 22, 24.
It is to be appreciated, and as illustrated in FIG. 3a, that main
housing 30 is attached to cool air return 12 or other appropriate
location on the forced air heating and cooling system A. The
attachment is made through screw holes 64a, 64b, 64c or by other
appropriate attachment, for example by an adhesive arrangement,
etc. A benefit obtained by the construction of main housing 30 is
the minimal intrusion on the integrity of the cool air return 12
caused by attachment. The use of screws or other attaching devices,
through holes 64a-64c and lamp passage openings 66a-66b allow for
housing unit 30 to be permanently attached to cool air return 12
with minor cutting of the sheet metal, thereby facilitating easy
installation. As previously discussed, lamp cartridges 22 and 24
may be inserted into and removed from housing 30 simply by pulling
or pushing handles 42 or 44. Therefore, no tools are needed to
remove or insert lamp cartridges 22, 24.
Ballasts 46 and 48 are of a type appropriate for use with
ultraviolet germicidal lamps.
FIG. 8 depicts the wiring layout of ultraviolet sterilization unit
10 of the present invention. In this embodiment, the sterilization
unit includes two lamps and is constructed such that when one lamp
is removed from housing 30 both lamps are de-energized. Through
this configuration, no ultraviolet light is emitted from the
opening of the removed lamp cartridge 22, 24. One manner in which
to obtain the above results is to interconnect lamp cartridges 22,
24 in series with each other. This is accomplished by having power
supplied by line 18 to cartridge sockets 50, 52 in turn supply the
oppositely corresponding ballast 46 and 48.
In particular, line 70a is shown as being supplied to a pin of a
six pin recepticle cartridge socket 50'. When six pin plug
cartridge 36' is engaged with cartridge socket 50', a connection is
made from line 70a through line 70b, 70c and 70d whereby line 70d
is input 70e to ballast 48. Similarly, power is supplied to six pin
recepticle cartridge socket 52' at line 72a. When then connected to
six pin plug cartridge 37' a circuit is provided to line 72b, 72c
and to 72d which in turn supplies ballast 46 at input 72e. Through
this arrangement, when either of the cartridge plug/cartridge
socket combinations, (i.e. 36' and 50' or 37' and 52') are
disconnected thereby de-energizing an associated lamp (26 or 28),
the other lamp (26, 28) is also de-energized.
The remaining four pin recepticles of cartridge sockets 50' and 52'
connect to the corresponding pins of cartridge plugs 36' and 37',
providing a path from ballasts 46, 48 to cartridge plugs 36' and
37'. Cartridge plugs 36' and 37' are in turn wired to lamp sockets
38 and 39. Thus, when lamp sockets 38 and 39 receive the prongs of
associated ultraviolet lamps 26 and 28 a complete electrical path
is provided for energizing ultraviolet lamps 26 and 28.
FIG. 9 is a cross-sectional view of ultraviolet sterilizer unit 10,
where lamp cartridges 22 and 24 are inserted within main housing
30. Taking a cross-section view of ultraviolet sterilizer unit 10
results in ultraviolet lamp 28 being shown in cross-section while
ultraviolet lamp 26 is shown whole. This view emphasizes the
previously discussed offset of lamps 26, 28.
FIG. 9 also illustrates that when lamp cartridges 22 and 24 are
inserted into housing 30, locking interconnections ensure there is
no direct path for light to pass out of the rear of housing 30.
Light from lamps 26 and 28 is blocked from exiting through housing
30 on the cartridge insertion side of the housing by including
bends and angles to block light. A further feature of housing 30
are gaskets 76a, 76b and housing gasket 77 used to ensure air from
system A does not leak out of sterilization unit 10. Specifically,
housing gasket 77 is placed between the wall of system A where
openings have been made for insertion of lamps 26, 28 and the face
of housing 30 acting as a seal. Gasket rings 76a, 76b are also used
to ensure air does not exit through the interface between lamp
cartridges 22, 24 and housing 30.
While in the first embodiment ultraviolet lamps 26 and 28 were
single ended lamps wherein internal conductive material provide the
conduction path from one end of the lamp to another, thereby
creating a circuit, two ended lamps may also be used as shown in
FIG. 10. In this embodiment, external wires 80 and connector 82 are
provided to the far end of the lamp 84 to connect to prongs 86
thereby providing a complete circuit. Such an arrangement may
require slightly larger openings in the duct work. However, the
external wires and connectors can still be arranged to be carried
as part of the lamp cartridge, so that when the lamp cartridge is
removed, the external wires and connectors at the far end of the
lamp are at the same time removed.
It is noted ultraviolet sterilization unit 10 is shown in FIG. 3a
and 3b as being substantially in a horizontal relationship to the
cool air return duct 12, particularly, handles 42 and 44 are
perpendicular to the bottom of cool air return 12. However,
sterilization unit 10 may be inserted in any angled position, i.e.
housing 30 may be rotated 90.degree. from what is shown in FIG. 3a.
This capability is desirable to ensure that as much of a
cross-sectional area of the air heating and cooling system is
covered by the ultraviolet lamps 26, 28 as possible. Specifically,
it is desirable to have the lamps located at substantially right
angles to air flow so that air in the full height of the duct is
irradiated, and rotation of unit 10 provides this ability.
While the above invention has been described in detail in
connection with a two lamp unit, it is to be appreciated that the
present teachings may be extended into multi-lamp units to provide
a higher degree of sterilization.
The invention has been described with reference to the preferred
embodiment. Obviously, modifications and alterations will occur to
others upon a reading and understanding of this specification. It
is intended to include all such modifications and alterations
insofar as they come within the scope of the appended claims or the
equivalents thereof.
* * * * *